INVALID_TRANS_TYP from get() on SalesOrder

Hi all, I've been trying to retrieve a specific SalesOrder using the get() method but getting an error.

It works splendidly with InventoryItem, but with SalesOrder I get the following response error:

Accellos.Integrations.A1WtoNetSuite.com.netsuite.webservices.StatusDetailCodeType.INVALID_TRANS_TYP

"Transaction type specified is incorrect."

Code:

            RecordRef soRecord = new RecordRef()
            {
                internalId = "734",
                name = "A Wolfe",
                type = RecordType.salesOrder,
                typeSpecified = true
            };

            ReadResponse response = NetSuiteService().get(soRecord);


I've tried with and without the name/entity parameter but nothing seems to work. The orders I'm attempting are in Pending Fulfillment status. Everything I've researched so far hints that this should work. Any ideas?